ARCHIVED REPORTS_XR0011013 - Laserfiche WebLink

Home Browse Search

I EXECUTIVE SUMMARY I This is a report of Kleinfelder's Fourth Quarter 2003 groundwater monitoring for the former Disco Facility located at 110 North Filbert Street in Stockton, California. On November 10, 2003, twenty (20) monitoring wells and three (3) piezometers were sounded for depth to groundwater. On November 19 and 20, 2003, seven (7) monitoring wells were sampled by Kleinfelder. The monitoring wells sampled were MW-DIS-11s, MW-DIS-11d,MW- DIS-12, MW-DIS-13, MW-DIS-14s, MW-DIS-14d and MW-DIS-15. The monitoring wells were sampled in accordance with the "Groundwater Monitoring Frequency Decision Tree" developed by CH2M Hill. The depth to groundwater ranged from 45.86 feet below the top of the well casing (MW-DIS- I Is) to 55.46 feet below the top of.the well casing (MW-DIS-15). Groundwater elevations for the monitoring wells ranged from —34.93 feet (MW7DIS-5) to —35.78 feet (MW-DIS-15). Groundwater flow direction at the site is estimated to be towards the east/southeast at approximately 0.002 ft./ft. A localized groundwater mound was noted near MW-11s, MW-11d, . and MW-14s whereas, a localized depression was noted near MW-DIS-15. These localized anomalies may be a result of the ozone sparging activities currently being performed directed near these locations. The 7 groundwater samples were analyzed for the following: benzene, toluene, ethylbenzene, and total xylenes (BTEX), Total Petroleum Hydrocarbon as gasoline (TPH-g), 1,2-Dichloroethane (1,2-DCA), 1,2-Dibromoethane (EDB), and Tert-Butyl Alcohol (TBA). Only one groundwater sample (MW-DIS-15) was additionally analyzed for all of the oxygenates Di-isopropyl Ether (DIPE), Ethyl t-Butyl Ether (ETBE), Methyl tert-Butyl Ether (MTBE), and tert-Amyl Methyl Ether (TAME). MW-DIS-14s-was additionally analyzed for MTBE. TPH-g was not detected in any of the groundwater samples collected this quarter. Similarly, BTEX compounds were not detected in any of the groundwater samples analyzed. EDB was not detected in any of the groundwater samples collected this quarter. 1,2-DCA was detected in 3 of the 7 gro>_umdwater samples. The detected concentrations ranged from 1.4 µg/1 (MW-DIS-12) to 96 �Lg/1 (MW-DIS-11s). The detected concentration of 1,2-DCA exceeded the Primary Maximum Contaminant Level .(PMCL) for 1,2-DCA of 5 µg/l in the sample collected from MW-DIS-11 s and MW-DIS-15. MTBE was detected in MW-DIS-14s with a concentration of 0.50 µg/l. The Primary Maximum Contaminant Level (PMCL) for MTBE is 13 µg/1 and the Secondary Maximum Contaminant Level (SMCL) for MTBE is 5 �tg/l. The detected concentration of MTBE in MW-DIS-14s does not exceed the. PMCL or the SMCL for MTBE this quarter. There were no detectable 12280.MON/ST03R1875 Page I of 13 2004,Kleinfelder,Inc February 9,2004 KLEINFELDER 2825 East Myrtle Street,Stockton,CA 95205-4794 (209)948-1345 (209)948-0621 fax